For many years, halogenated hydantoins have been employed in aqueous systems for a variety of applications. To a large extent, the halogenated hydantoins have been utilized for bleaching purposes as described, for example, in U.S. Pat. Nos. 4,078,099; 3,575,865; 3,481,878; 3,406,116 and 2,921,911.
Halogenated hydantoins have also been known to be effective for scouring, cleansing and disinfecting applications as illustrated by U.S. Pat. Nos. 2,789,078; 3,702,826 and 3,583,922.
Automatic dishwashing compositions of halogenated hydantoins are also well known as taught for example by U.S. Pat. No. 4,102,799.
The treatment of cooling tower waters, swimming pools and the like systems with halogenated hydantoins is illustrated in U.S. Pat. Nos. 4,297,224 and 3,412,021.
In many of these applications, it has been desirable to utilize the halogenated hydantoins in an agglomerated form as described in the aforementioned U.S. Pat. No. 3,412,021 so as to control the release of the halohydantoin.
Known methods of agglomerating halohydantoins generally involve conventional pelletizing or briquetting operations which may require use of binders or sticking agents. It has also been proposed to use compacting rolls to fabricate the halohydantoins into various forms.
These current methods are severely hindered by the very dusty and corrosive nature of the halogenated hydantoins, which has contributed to high maintenance costs for equipment and unsatisfactory work environments. Furthermore, the halogenated hydantoins are susceptible to decomposition due to conditions of high humidity or excessive temperatures generated during processing in these procedures. Any acidic by-products of the decomposition could corrode metal surfaces, contaminate the product, and catalyze further decomposition.
Agglomerating discs (often referred to as "disc pelletizers") have developed in the art of "balling" in an attempt to eliminate dusting problems. While agglomerating discs are employed for a variety of industrial applications, no means has been provided heretofore for using such equipment in the agglomeration of halohydantoins.
It is therefore a primary object of the present invention to provide a method for agglomerating halogenated hydantoins into a spherical form having a hard structural integrity.
A further object of the present invention is to provide spherical agglomerates of halogenated hydantoins which, when placed in water, retain their shape and integrity for periods of time sufficient to provide a uniform and controlled release of the active halogen.
Still a further object of the present invention is to provide an improved means for the disinfecting of recirculating aqueous systems through the controlled release of active halogen.
These and other objects of the invention will become more apparent from the discussion which follows.